The should get 8 cms (3 inches approx), but you don't se many that size because they're so inbred. My advice with rams is look for good ones, that look big, no bent fins, amazing colour as there is a ton of inbred rubbish swimming around that has dull colours, is small, and dies a lot. If you see some apistos or something you like , get them instead, as you're going to have to look hard for good rams.